Nutraceuticals and Functional Foods
Robert E.C. Wildman, Richard S. Bruno in Handbook of Nutraceuticals and Functional Foods, 2019
The non-starch polysaccharides can be divided into homogeneous and heterogeneous polysaccharides, as well as into soluble and insoluble substances. Cellulose is a homogeneous non-starch polysaccharide, as it consists of repeating units of glucose monomers. The links between the glucose monomers are β1-4 in nature. These polysaccharides are found in plant cell walls as microfibril bundles. Hemicellulose is found in association with cellulose within plant-cell walls and is composed of a mixture of both straight-chain and highly branched polysaccharides containing pentoses, hexoses, and uronic acids. Pentoses such as xylans, mannans, galactans, and arabicans are found in relatively higher abundance. Hemicelluloses are somewhat different from cellulose in that they are not limited to glucose, and they are also vulnerable to hydrolysis by bacterial degradation.
Microalgae for Human Nutrition
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
Microalgae are also a good source of carbohydrates (Table 16.1), found in the form of starch, cellulose, sugars and other polysaccharides (Becker 2004; Chácon-Lee and González-Mariño 2010; Matos et al., 2017). These compounds provide energy used or stored by microalgal cells and as structural elements (Wells et al., 2017). Carbohydrates are important sources of energy in the human diet. Presently, in most cases, the microalgal food market is associated with the consumption of the whole biomass. This means that, in addition to the consumption of proteins, other components of the microalgal biomass such as lipids and carbohydrates are also consumed (Becker 2004). It is fair to say that algal polysaccharides are the least acknowledged algal-derived compound already being consumed as food and additives. Studies indicate that the human organism possesses enzymes capable of the hydrolysis of some carbohydrates in mono- and disaccharides, but it cannot digest the more complex ones such as cellulose, hemicellulose and pectin (Wells et al., 2017). A fraction of these indigestible carbohydrates has beneficial physiological effects for the human organism. It is therefore considered as functional food and is often referred to as dietary fiber (Wells et al., 2017). These carbohydrates resist digestion in the upper part of the gastrointestinal tract due to the presence of glycosidic bounds that are different from the digestive enzyme–susceptible α-1,4 and α-1,6 linkages (Aluko 2012; Wells et al., 2017).
Beneficial Lactic Acid Bacteria
K. Balamurugan, U. Prithika in Pocket Guide to Bacterial Infections, 2019
To cheapen production of various compounds generated by LAB, especially lactic acid, new substrates have been tested because of high cost of the raw materials, such as starch and refined sugars. Lignocellulosics due to their abundance, low price, high polysaccharide content, and renewability have been chosen as potential carbohydrate feedstock; however, LAB were not able to use these substrates without pretreatment. Various physical, chemical and biological methods were used to remove lignin, separate cellulose and hemicellulose, increase the accessible surface area, partially depolymerize cellulose, and enhance porosity of the materials to promote the subsequent action of the hydrolytic enzymes. Enzymatic hydrolysis converts the polysaccharides remaining after pretreatment in the water-insoluble solid fraction into soluble sugars further utilized by LAB (Abdel-Rahman et al. 2011). Compounds toxic to fermentative organisms such as furfural, phenolic derivatives, and inorganic acids are also released during pretreatment, urging to seek resistant bacteria or carry out detoxification (Guo et al. 2010). Other wastes can be used as substrates for LAB; however, they are often subjected to either pretreatment or supplementation of missing compounds as carbon sources or minerals (Dumbrepatil et al. 2008; Pacheco et al. 2009; Panesar et al. 2010; Özyurt et al. 2017).
Adsorption of water pollutants using H3PO4-activated lignocellulosic agricultural waste: a mini review
Published in Toxin Reviews, 2023
Lawal Sirajo, Muhammad Abbas Ahmad Zaini
Several methods are available to remove water pollutants, each with merits and drawbacks (Cheremininoff 2002; Klasson et al. 2009; Hock and Zaini, 2018; Amran and Zaini 2020). Adsorption is a preferred method for wastewater treatment because of the following advantages: low-cost of operation, ease of operation and implementation, wide selection of adsorbents and activated carbons, and high efficiency (Dotto and McKay 2020). The process allows the exploitation of lignocellulosic agricultural wastes (LAW) as feedstock of activated carbon (AC). Lignocellulosic material is a natural polymer, composed of cellulose (42-50%), hemicellulose (19-25%) and lignin (16-25%) (Mi et al. 2015; Yinon et al. 2018; Hemavathy et al. 2021). Coconut shell, fruits stone, palm kernel shell, orange peel, sugarcane waste etc. are examples of inexpensive LAW for AC production. At high temperature, the polymeric structure decomposes and liberates volatiles in the form of tars and gases, leaving the rigid carbon skeleton of aromatic slips and tiles (Derbyshire et al. 1995; Albulencia et al. 2012; Mohamed et al.2018).
Polybia occidentalis and Polybia fastidiosa venom: a cytogenotoxic approach of effects on human and vegetal cells
Published in Drug and Chemical Toxicology, 2021
Marcel José Palmieri, Amanda Ribeiro Barroso, Larissa Fonseca Andrade-Vieira, Marta Chagas Monteiro, Andreimar Martins Soares, Pedro Henrique Souza Cesar, Mariana Aparecida Braga, Marcus Vinicius Cardoso Trento, Silvana Marcussi, Lisete Chamma Davide
However, plant cells have cell walls that are a barrier for the passage of the various molecules, impeding the venom to spread. The primary cell walls are composed of cellulose microfibrils embedded in a highly hydrated matrix, composed of pectin and hemicellulose. Structural proteins are added to the cellulose/hemicellulose scaffolding to help stabilize the cell wall. The primary cell wall is composed of approximately 25% hemicellulose, 35% pectin, and 25% cellulose, with structural proteins varying in frequency up to a total of 8%. These values may vary according to the species and environmental influences (Taiz and Zeiger 2002). This complex structure is likely being disrupted by the action of the many proteases and peptides that compose the Polybia venom. They could be acting on the structural proteins or directly on the cell wall matrix, reducing its cohesion and therefore increasing its permeability. Furthermore, cell walls are naturally permeable to small molecules (Knox and Benitez-Alfonso 2014).
Recent advancements in cellulose-based biomaterials for management of infected wounds
Published in Expert Opinion on Drug Delivery, 2021
Munira Momin, Varsha Mishra, Sankalp Gharat, Abdelwahab Omri
Cellulose acquired from vegetal origin is associated with residual hemicellulose, lignin, and pectin. Microbial or bacterial cellulose (BC) is a very unique biopolymer, mostly synthesized from Acetobacter xylinum, with several properties, which make it exceptionally valuable in the biomedical field [162]. The features that make it superior to plant-based cellulose are its high chemical purity, porosity, and permeability [163]. BC has many inherent properties making it an ideal scaffold for burns, tissue regeneration and as artificial skin [164]. The important characteristics are its nontoxicity, non-carcinogenicity, and biocompatibility. Moreover, it can absorb exudates from the wounds and accelerate granulation, making it a promising class of material for wound dressing [165,166]. The exceptional physical as well as mechanical properties of BC are attributed to its unique 3D structure, which is considerably different from the vegetal sources and BC aggregates to form elongated fibrils, which gives it a high surface area and more flexibility as compared to the plant-based cellulose. The fibers of BC are many folds thinner and smaller, making it highly porous Table 4 [167].